1. Field of Invention
The present invention relates to an apparatus for performing processing in the production of semiconductor devices, such as integrated circuits. The present invention also relates to a method of preventing a deposited film within the apparatus from peeling. The apparatus for treatment is suitable for dry etching and plasma CVD.
2. Description of Related Art
Production of semiconductor devices employs various technologies, such as dry etching and CVD. They are designed to etch surface layers on semiconductor substrates or form films on substrates by plasma decomposition or thermal decomposition of gases. Parts of decomposition products are inevitably deposit and build-up on interior components within the processing chamber, including the inner wall of a processing chamber itself. Resulting film of deposited material peels and generates particles within the chamber, or drops off on the substrate to form apparent defects.
In order to circumvent this problem, it is necessary to perform mechanical cleaning periodically on the processing apparatus. Unfortunately, mechanical cleaning takes a long time because it requires that the chamber be opened. Once opened, the chamber needs temperature adjustment and complete evacuation prior to restarting the processing. Hence, the mechanical cleaning greatly redness the operation rate of the apparatus. Therefore, several methods have been proposed to reduce the frequencies of mechanical cleaning.
One of them is dry cleaning with various reactive gases. Dry cleaning evaporates and removes the deposited materials and reduces the generation of particles. However, dry cleaning usually employs a plasma-excited gas. Therefore, the cleaning is incomplete in the area that is not exposed to the plasma. This is true particularly for an apparatus of parallel plate structure with a narrow gap, since the plasma in a narrow gap apparatus is confined in a limited portion within the chamber. Similarly, dry cleaning with a gas excited by any other known method than plasma cannot achieve complete cleaning in the chamber.
A method to prevent deposited films from peeling is disclosed in Japanese Patent Laid-open Nos. 196421/1994 and 163180/1998 and U.S. Pat. No. 5,474,649. It achieves the object by roughening the surface of the inner wall of the chamber, or the surface of interior components in the chamber, for good adhesion of the deposited film. This surface roughening is accomplished by frost treatment (bead blasting), engraving, etching, molding, or the like.
However, the frost treatment is effective only so long as the film of deposited material is relatively thin and has a relatively small internal stress. As the deposited film grows to tens or hundreds of micrometers thick, the adhesion strength produced by frost treatment is not enough to keep it on the inner wall of the chamber or the surface of the interior components.
On the other hand, various interior components in the processing chamber, including inner wall of the chamber itself of the apparatus for dry etching and CVD, often have a surface coated layer. Such costing on the surface may peel after repeated use due to deterioration. This also poses a problem as in the case of the peeling of deposited materials mentioned above.
In order to solve this problem, there has been proposed an idea of replacing the deteriorated parts. To put this idea into practice, there has been proposed a processing chamber which is provided with an inner wall of double layer structure so that the deteriorated part can be removed for replacement.
However, the inner wall of double-layer structure still requires periodic replacement. Hence it is not quite helpful to reduce the frequency of opening the chamber. There still exists a problem of a low operation rate.
The present invention addresses the above-mentioned problems. It is an object of the present invention to provide an apparatus and a method for processing semiconductor substrates in the production of semiconductor devices. It is another object of the present invention to provide a method of preventing deposited film in said apparatus from peeling. The apparatus and method according to the present invention prevent deposited film and surface coating from peeling, thereby reducing particles in the chamber and increasing the operation rate of the apparatus.
According to one aspect of the present invention, an apparatus for processing a workpiece for production of semiconductor devices comprises a processing chamber that mounts the workpiece, the processing chamber including an interior component having a stepped surface region comprising a plurality of sectioned areas divided by steps.
Preferably, the sectioned areas arranged according to the temperature gradient produced on the surface of the component during operation of the apparatus.
Preferably, the stepped region is located in a position where a film of deposited material is formed thereon during operation of the apparatus; and the steps are high enough to prevent the deposited film from peeling.
Still preferably, the stepped region is located in a position where a film of deposited material is formed thereon during operation of the apparatus; and the sectioned surface region prevents the deposited film from peeling by dividing the deposited film into sections having appropriate sizes.
According to another aspect of the invention, a method to prevent peeling of a deposited film in an apparatus used in production of a semiconductor device, comprises providing a processing chamber that mounts a workpiece to be processed therein, the processing chamber including an interior component having a stepped surface region comprising a plurality of sectioned areas divided by steps; processing the workpiece in the processing chamber while forming a film of deposited material on the stepped surface region; wherein the steps are high enough to prevent the deposited film from peeling.
According to another aspect of the invention, a method of processing a semiconductor substrate comprises: providing a stepped region on a surface of an interior component in a processing chamber, the stepped region including a plurality of sectioned areas divided by steps; placing a semiconductor substrate to be processed in the processing chamber; and processing the semiconductor substrate within the processing chamber while forming a film of deposited material on the stepped region; wherein the steps are provided such that the deposited film is effectively divided.
Preferably, the sectioned areas include a plurality of raised sections and recessed sections divided by the steps, and adjacent raised sections are sufficiently separated to effectively divide the deposited film.
Preferably, angles of the steps are sufficient to effectively divide the deposited film.
Preferably, the steps are sufficiently high so that the film is effectively divided.
Still preferably, the method further comprises repeating the placing and processing until a cumulative time of the processing reaches a predetermined value; wherein the steps are provided such that the deposited film is effectively divided so that peeling of the film built-up during the predetermined cumulative processing time is prevented.
According to another aspect of the invention, a method of processing a semiconductor substrate comprises: providing a stepped region on a surface of an interior component in a processing chamber, the stepped region including a plurality of raised sections divided by grooves; placing a semiconductor substrate to be processed in the processing chamber; and processing the semiconductor substrate within the processing chamber while forming a film of deposited material on the stepped region; wherein the steps extend substantially perpendicular relative to the sectioned areas.
According to another aspect of the invention, a method of processing a semiconductor substrate comprises: providing a stepped region on a surface of an interior component in a processing chamber, the stepped region including a plurality of raised sections divided by grooves; placing a semiconductor substrate to be processed in the processing chamber; and processing the semiconductor substrate within the processing chamber while forming a film of deposited material on the stepped region; wherein the grooves are one-dimensional grooves.
Preferably, the film is deposited on a ring-shaped area, and the grooves are arranged generally perpendicular to a circumferential direction of the ring-shaped area.
Preferably, the interior component has an inner periphery surrounding the semiconductor substrate placed in the processing chamber, and the grooves are arranged in a vicinity of, and generally perpendicular to, the inner periphery of the component.
Preferably, a temperature gradient is produced on the stepped region during the processing of the substrate, and the grooves are arranged generally along directions of the temperature gradient.
According to another aspect of the invention, an interior component of a processing chamber that processes a semiconductor substrate, comprises: a stepped region including a plurality of sectioned areas divided by steps; wherein the steps extend substantially perpendicular relative to the sectioned areas.
According to another aspect of the invention, a focus ring that surrounds a semiconductor substrate in a plasma processing apparatus comprises: a stepped region formed in a vicinity of an inner periphery of the focus ring, the stepped region including a plurality of raised sections divided by grooves; wherein the grooves are arranged in a vicinity of, and generally perpendicular to, the inner periphery of the focus ring.